Two-position valve



A. BENDER TWO-POSITION VALVE Aug. 13, 196 8 2 Sheets-Sheet 1 Filed Oct.18, 1966 Alfred Bender INVENTOR.

BY Jlcslml, Tm 5' Jam Aug. 13, 1968 Filed Oct. 18, 1966 2 Sheets-Sheet 2Fig.4

Fig. 3

Alfred Bender INVENTOR.

To 8 .zudbm United States Patent 7 Claims. (Cl. Han-625.65

This application is a continuation-in-part of my application Ser. No.412,379, filed Nov. 19, 1964, and now abandoned.

The present invention relates to two-position or socalled two-pressurevalves for fluid-operable systems and, more particularly, to a valve ofthis character for hydraulic or pneumatic control systems.

Hydraulic or pneumatic control devices have, heretofore, been providedwith control valves manually, remotely or automatically operable to cutoff the flow of operating fluid from the source of fluid pressure to thefluidresponsive device and, generally, to connect this device to areservoir or other storage means for the fluid. For the most part, suchvalves have been of the two-position type wherein a valve member isdisplaceable between a first position in which the source of fluid underpressure communicates with the fluid-operated device directly or viasome force-amplifying or force-attenuating means, and a second positionwherein the fluid-responsive device is discharged; when a hydraulicmedium is employed, the liquid is returned through the valve to areservoir from which the source of fluid pressure can be supplied. Ithas, moreover, been proposed to hold the valve member in one of itsextreme positions by the fluid pressure at the valve and to employ anextraneous force (e.g., magnetic) for holding the valve member in itsother extreme position. The disadvantages of such a system are obviousin that high fluid pressures and large flow apertures requirecorrespondingly high extraneous forces if the valve member is to be heldsecurely in its extreme position. Large forces of this character requirecorrespondingly large permanent or electromagnet or other sources offorce urging the valve member against the second seat.

It is, therefore, the principal object of the present invention toprovide a two-position valve of the character described for the controlof fluids under pressure whereby massive means for applying extraneousforces are not required.

Still another object of this invention is to provide a valve of thecharacter described which is simple and of economical manufacture butwherein the valve member can be held securely in either of its extremepositions without the expenditure of large forces extraneous to thefluid system.

Another object is to extend the principles originally set forth in mycopending application mentioned above.

These objects and others which will become apparent hereinafter areattained, in accordance with the present invention, by the provision ofa two-position or twopressure valve whose valve member is provided withdifferential-piston means having first and second effective surfaceareas exposed to fluid under pressure and at low pressure, respectively,and adapted to bias the valve member toward one of its extreme positionsand against a first valve seat in blocking relationship therewith; thevalve further comprises means for applying an extraneous force to thevalve member in the direction in which the valve member is biased by thenet fluid force applied to said different piston. The force-applyingmeans thus acts in aiding relationship with the fluid force applied toone ef- 3,396,751 Patented Aug. 13, 1968 fective surface area and thesum of these forces at least balances the fluid force applied to thelarger effective area of the valve member when the valve member is inblocking engagement with a second valve seat.

According to a more specific feature of the present invention, theforce-applying means and the effective piston surfaces of thedifferential piston are aligned in the direction of displacement of thevalve member and are preferably aligned therewith and with the first andsecond valve seats spaced apart in this direction. The valve seatsshould have, according to the principles of the present invention,approximately the same cross-sectional areas, these areas lyingtransversely to the direction of displacement of the valve member andthe differential piston so as to expose effective surfaces of the valvemember to fluid pressure in additive or subtractive relationship withthe larger or smaller surfaces of the differential piston. Thus, thepresent invention contemplates the provision of a valve seat at apassage interconnecting a compartment of the valve communicating withthe fluid-responsive or fluid-operated device and interconnecting thelatter with, for example, a reservoir (in the event a hydraulic mediumis employed) or the atmosphere (in the case of a gaseous fluid). Theother valve seat is disposed between the source of fluid pressure andthe aforementioned compartment in communication with the fluid-operateddevice (e.g., a hydraulic or pneumatic cylinder-and-piston arrangement,motor or the like) or with a further compartment communicating with thedevice.

Still another specific feature of this invention resides in theprovision of a pressure chamber exposed to the pressure of a fluid ascommunicated through the passage along which the first valve seat isprovided and formed with at least part of the larger effective area ofthe differential piston; another pressure chamber is formed between thedifferential piston and the force-applying means and communicates withthe source of fluid under pressure at the valve inlet. Theforce-applying means is, according to this invention, constituted by atwo-condition polarized magnet whose axially displaceable core orarmature is composed of magnetic material and is affixed to thedifferential-piston and valve member. Any convenient solenoid-type coilcan be employed as the magnet means although it is also possible to makeuse of permanent magnet systems displaceable into the proximity of thecore.

In a preferred embodiment of the invention, the valve member is a ballto which a piston is secured, the high pressure of the source acting inopposite directions upon the valve member and the differential piston.Thus the latter may have its full surface area exposed to the fluidpressure of the outlet (in the blocked condition of the inlet) whilesource pressure acts upon the valve member to urge it away from its seatand upon the piston in the opposite direction. The piston has, inaccordance with this phase of the invention, a surface area equal tothat of the valve member exposed to source pressure and likewise exposedto source pressure while being effective to hold (with the aid of thebistable or reversible polarized magnet) the valve member in itsinlet-blocking position. When the holding force of the magnet isreleased, however, the valve member may move only under the effect offluid pressure to connect the source with the load and blockcommunication between the latter and the outlet. Since the larger faceof the differential piston is exposed to the discharge or back pressureand source pressure continues to be applied to the equal but oppositelyeffective surfaces of the valve member and differential piston, thedifferential action serves to open the valve.

The above and other objects, features and advantages of the presentinvention will become more readily apparent from the followingdescription, reference being made to the accompanying drawing in which:

FIG. 1 is a vertical cross-sectional view through a twoposition valve,according to the present invention, in one of its operative positions;

FIG. 2 is a view similar to FIG. 1 showing the valve in its otherextreme position; and

FIGS. 3 and 4 are views similar to FIGS. 1 and 2 showing another valveassembly.

In the drawing I show a valve housing 1 in which a valve body 2 isreciprocable between its upper position in which it engages the annularvalve seat 16 and its low er position of engagement with a valve seat 17of similar cross-sectional area. The valve member 2 is connected by arod 21 with a differential piston 4, while this piston has a shaft 18guided in the bore 19 of the housing and forming the movable core of anannular magnet 3. An inlet 5 of the valve housing 1 is supplied withfluid under pressure from a pump 22 which draws the hydraulic mediumfrom a reservoir R. The valve seat 16 is interposed between the inlet 5and a port 6 supplying hydraulic fluid to a fluid-responsive orfluid-operated device, such as the hydraulic working cylinder C. Theport or passage 6 communicates with the chamber 8 in which the sphericalvalve body 2 is displaceable and separates this chamber from the chamber9 to which the effective surface 21 of the piston 4 is exposed. The seat17 thus surrounds a passage 11 in the partition between the compartments8 and 9. A duct 7 connects compartment 9 with the reservoir R in thereturn path for the hydraulic medium. At the other end of differentialpiston 4, the valve housing is provided with a chamber 12 which ismaintained at the supply pressure of inlet 5 via duct 13. An annularleakage compartment 14 is interposed between the chamber 12 and theexterior along the shaft 18 and its bore 19 to accumulate oil tending toleak under pressure along the shaft 18 and return it to the reservoir.

As previously noted, the valve body 2 is constituted substantially as asphere or ball so that the annular valve seats 16 and 17, which haverelatively large cross-sections, define the same effective areas withrespect to fluid pressure applied to the valve member. It is evidentthat the fluid pressure applied to a ball is effective over the areaexposed to the fluid and projected on a plane perpendicular to thedirection of movement of the piston. When the valve member 2 is in allaround engagement with the seat 16 and blocks communication of fluidfrom the inlet 6 to the working cylinder C via chamber 8 and passage 6,the cylinder C communicates via the passage 6, the chamber 8, theunblocked valve seat 17, the passage 11, the chamher 9 and the passage 7with the reservoir to de-energize the cylinder. When, however, the valvemember 2 engages valve seat 17 in blocking position, hydraulic mediumcan flow from the pump 22 via inlet 5, chamber 8 and passage 6 to theworking cylinder, the return stream to reservoir R being terminated.

The effect of the differential piston, as will be evident hereinafter,is to reduce the force which must be applied to the extraneous means(i.e., the electromagnet 3) to shift the valve member from one of itsoperative positions to the other. Thus, when the valve body 2 anddifferential piston 4, both of which constitute the valve member, are inthe position shown in FIG. 1, the pressure P of pump 22 is effectiveover the cross-sectional area A of the valve seat 16 to urge the valvebody 2 downwardly. The surface 21 of differential piston 4, whose areawill be denoted as A is at the pressure P, of the reservoir or, as thecylinder C discharges, at the pressure P of the fluid from the cylinderpassing through chamber 9 to the reservoir. The oppositely effectivesurface of piston 4 has its area A exposed to the pump pressure P viaduct 13. The cross-sectional area of shaft 18 will be designated as Afor the present purposes. In order for the valve body 2 to be heldsecurely against the valve seat 16 in the position shown in FIG. 1, aforce F must be applied by the polarized magnet 3 to the shaft 18 whichis equal to or just slightly greater than the produce P A Thisrelationship is readily discernible since the force acting upon thevalve body to hold it against the seat 16 is the sum P XA +F +P X(A Awhile the force acting in the opposite direction is the sum P A +P A Forthe sake of this discussion, P can be considered equal to P and bothequal to 0. If the diameters of areas A, and A are assumed to be equal,it will be evident that the force F would have to be at least equal to PA This can be seen in a simplified manner by noting that the pressure ofthe fluid from the cylinder is appliedto similar areas of theball-shaped valve body 2 and the piston member 4 except that it is lesseffective in the direction of seat 16 by virtue of the presence of shaft18. This difference in the efiectiveness of the fluid pressure issupplied by the magnetic means. The two-condition magnet means can beany convenient solenoid arrangement as disclosed, for example, incommonly assigned copending application Ser. No. 327,198, filed Dec. 2,1963, by myself and others, now Patent No. 3,305,209. In a simplifiedform, the magnet is seen to include a solenoid coil 3 which isenergizable from a DC. source and a polarized core 3 mounted on orintegral with the shaft 18. With the system in the position shown inFIG. 1, the cylinder C discharges fluid into the reservoir R. The forceF of the magnet acts in aiding relationship with the pressure in chamber12 and thus can be relatively weak. In fact, since the pressure inchamber 12 is always equal to that supplied by the pump, the valve cancontrol substantially any pressure with substantially the same magneticforce although the pistons may be higher or lower in accordance with therequirements of this system. It may be observed that seldom, if ever, isthe pressure of fluid discharged from the cylinder and applied tosurface 21 greater than that applied to the pump, since chamber 9 is inpermanent connection with the outlet 7.

When the magnet is de-energized or preferably reversed with the valvemember 2, 4 moving in the direction of the valve seat 17, the passage 11is blocked so that the working cylinder C is supplied with fluid fromthei nlet 5 at the pump pressure P The magnet is now forceless inpreparation for energization to block the influx of the hydraulicmedium. The force holding the member against the seat is now P XA P AThus, only the relatively weak force F is required to counter the pumppressure and drive the valve body 2 into engagement with the seat 16when the magnet 3 is re-energized.

According to an important aspect of this invention, the valve is shiftedwith a magnet of small dimension. The ball valve 102 is thus held in itsupper position (FIG. 3) in part by the pressure applied to the surfacewhich, in this case, has the same surface area as that represented at AThe valve is thus held closed partly by magnetic force and is shiftedautomatically (i.e., exclusively by fluid pressure). In FIGS. 3 and 4,the parts corresponding to those of FIGS. 1 and 2 are identified withsimilar reference numerals in the hundreds range.

The force relationships involved in this system will be apparent fromthe following equations. If the pressures are represented as previouslygiven, with P indicatng the pressure at the inlet 105, P the pressure atthe outlet 106 to the hydraulic motor, P the pressure at the outlet 107,and F the magnetic holding force (as applied by the magnet 103), thefollowing equations can be stated:

Since:

and

When the stem or rod 118 of the magnetic device 3 has a diameter of 4mm., and the return or back pressure P at the outlet 107 isapproximately 10 kp./cm. (a back pressure close to that prevalent inmost highpressure hydraulic systems), the magnetic holding force F isapproximately equal to 1.26 kp. This holding force is easily supplied byeven conventional light-weight and compact polarized reversing magnets.

The traction force which must be exerted to open the valve and permitcommunication between the inlet 105 and the outlet 106 to the hydraulicmotor can be computed as follows (F being designated as the tractionforce exerted by the magnet to shift the valve):

Consequently, under the same operating conditions as discussed above(back pressure of 10 kp./cm. and a rod diameter of 4 mm.), a traction of-1.26 kp. is required to open the valve. This of course means that, uponremoval of the magnetic holding force, e.g., deenergization of themagnet, both the magnet core and the valve member will shift into theother position (FIG. 4) to connect the inlet 105 with the load viaoutlet 106 only under the action of the fluid.

The invention as described and illustrated is believed to admit of manymodifications within the ability of persons skilled in the art; suchmodifications are considered to fall within the spirit and scope of theappended claims.

I claim:

1. A two-position valve for the control of a fluid under pressure,comprising a valve housing provided with an inlet for fluid underpressure, a port for supplying fluid to a fluid-responsive device, anoutlet for discharging fluid at low pressure from said housing, a firstpassage interconnecting said inlet and said port, and a second passageinterconnecting said port and said outlet; means in said housing forminga pair of spaced-apart valve seats, each along a respective one of saidpassages; a valve member reciprocably displaceable within said housingbetween a first position in blocking engagement with a respective valveseat and closing said first passage while permitting fluid flow fromsaid port to said outlet through said second passage, and a secondposition wherein said member is in blocking engagement with the other ofsaid seats to close said second passage and permit fluid flow from saidinlet to said port; two-condition magnetic force-applying meansoperatively connected with said valve member for displacing it from oneof said positions to the other in one operative condition of saidforceapplying means and permitting displacement of said valve memberfrom said other position to said one of said positions in a secondoperative condition of said force-applying means; anddifferential-piston means on said valve member having a first effectivesurface exposed to fluid pressure applied by said source at said inletand a second surface effective in a direction opposite to that of saidfirst surface and exposed to the pressure of fluid at said outletwhereby said valve member is displaceable solely by fluid pressure andthe action of said magnetic force-applying means between said positions.

2. A valve as defined in claim 1 wherein said valve member is linearlydisplaceable in said housing between said positions and said valve seatsare aligned with said valve :member but are spaced apart in thedirection of reciprocation thereof, said magnetic force-applying meanshaving an armature aligned with said valve member and affixed theretoremote from said valve seats.

3. A valve as defined in claim 2 wherein said first and second surfacesof said differential-piston mean-s are spaced along said valve member insaid direction between said armature and said valve seats.

4. A valve as defined in claim 3 wherein said valve body has a surfacearea exposed to the fluid pressure at said inlet equal to that of saidfirst surface of said differential piston and effective in the oppositedirection, said first surface being effective to urge said body intoblocking engagement with said valve seat of said first passage.

5. A valve as defined in claim 3 wherein said valve seats have identicalcross-sectional areas and said valve member includes a valve body rigidwith said differential piston means and disposed between said valveseats for selective engagement therewith.

6. A valve as defined in claim 5 wherein said valve body is generallyspheroidal and is connected with said differential piston means by anaxially extending rod.

7. A valve as defined in claim 5 wherein said valve housing is formedwith a first chamber surrounding said valve member remote from saidvalve seats and at least partly defined by said first chamber, and ductmeans formed in said housing communicating between said inlet and saidfirst chamber to apply fluid under pressure to said first surface, saidhousing further being formed with a second chamber between saiddilferential-piston means and said valve body communicating with saidoutlet and at least partly defined by said second surface formaintaining a low pressure at said second surface, said second passagecommunicating with said second chamber.

References Cited UNITED STATES PATENTS 2,723,681 11/1955 MacGlashan etal. 137625.65 2,895,089 7/1959 Leber 137--625.65 XR 2,930,404 3/1960Kowalski et a1. 137-62565 FOREIGN PATENTS 420,762 3/ 1967 Switzerland.

842,23 8 7/ 1960 Great Britain. 1,193,775 3/1958 France. 1,270,8229/1960 France.

M. CARY NELSON, Primary Examiner.

R. J. MILLER, Assistant Examiner.

1. A TWO-POSITION VALVE FOR THE CONTROL OF A FLUID UNDER PRESSURE,COMPRISING A VALVE HOUSING PROVIDED WITH AN INLET FOR FLUID UNDERPRESSURE, A PORT FOR SUPPLYING FLUID TO A FLUID-RESPONSIVE DEVICE, ANOUTLET FOR DISCHARGING FLUID AT LOW PRESSURE FROM SAID HOUSING, A FIRSTPASSAGE INTERCONNECTING SAID INLET AND SAID PORT, AND A SECOND PASSAGEINTERCONNECTING SAID PORT AND SAID OUTLET; MEANS IN SAID HOUSING FORMINGA PAIR OF SPACED-APART VALVE SEATS, EACH ALONG A RESPECTIVE ONE OF SAIDPASSAGES; A VALVE MEMBER RECIPROCABLY DISPLACEMENT WITHIN SAID HOUSINGBETWEEN A FIRST POSITION IN BLOCKING ENGAGEMENT WITH A RESPECTIVE VALVESEAT AND CLOSING SAID FIRST PASSAGE WHILE PERMITTING FLUID FLOW FROMSAID PORT TO SAID OUTLET THROUGH SAID SECOND PASSAGE, AND A SECONDPOSITION WHEREIN SAID MEMBER IS IN BLOCKING ENGAGEMENT WITH THE OTHER OFSAID SEAT TO CLOSE SAID SECOND PASSAGE AND PERMIT FLUID FLOW FROM SAIDINLET TO SAID PORT; TWO-CONDITION MAGNETIC FORCE-APPLYING MEANSOPERATIVELY CONNECTED WITH SAID VALVE MEMBER FOR DISPLACING IT FROM ONEOF SAID POSITIONS TO THE OTHER IN ONE OPERATIVE CONDITION OF SAIDFORCEAPPLYING MEANS AND PERMITTING DISPLACEMENT OF SAID VALVE MEMBERFROM SAID OUTER POSITION TO SAID ONE OF SAID POSITIONS IN A SECONDOPERATIVE CONDITION OF SAID